Abstract
GNSS attitude determination has been widely used in various navigation and positioning applications, due to its advantages of low cost and high efficiency. The navigation positioning and attitude determination modules in the consumer market mostly use low-cost receivers and face many problems such as large multipath effects, frequent cycle slips and even loss of locks. Ambiguity fixing is the key to GNSS attitude determination and will face more challenges in the complex urban environment. Based on the CLAMBDA algorithm, this paper proposes a CLAMBDA-search algorithm based on the multi-baseline GNSS model. This algorithm improves the existing CLAMBDA method through a fixed geometry constraint among baselines in the vehicle coordinate system. A fixed single-baseline solution reduces two degrees of freedom of vehicle rigid body, and a global minimization search for the ambiguity objective function in the other degree of freedom is conducted to calculate the baseline vector and its Euler angles. In addition, in order to make up for the shortcomings of short baseline ambiguity in complex environments, this paper proposes different validation strategies. Using three low-cost receivers (ublox M8T) and patch antennas, static and dynamic on-board experiments with different baseline length set-ups were carried out in different environments. Both the experiments prove that the method proposed in this paper has greatly improved the ambiguity fixing performance and also the Euler angle calculation accuracy, with an acceptable calculation burden. It is a practical vehicle-mounted attitude determination algorithm.
Highlights
With the continuous development of sensor technology, multi-source sensor fusion technology is increasingly used for navigation and positioning services in land vehicles and other applications with low-cost sensors
The primary baseline b1 is parallel to the vehicle moving searching, the CLAMBDA method is selected in this study, to fix the ambiguity
In order to solve this problem and improve the applicability of low-cost receiver attitude determination, this paper proposes a Euler angle search and single degree of freedom in an unfixed direction method called CLAMBDA-search, which adopts the CLAMBDA method to fix the ambiguity and the attitude parameters
Summary
With the continuous development of sensor technology, multi-source sensor fusion technology is increasingly used for navigation and positioning services in land vehicles and other applications with low-cost sensors. This requires accurate position and velocity information, and the vehicle attitude, to ensure every single sensor’s normal operation [1,2,3,4]. As an independent satellite-based positioning technology, GNSS is often used as an external reference for other technologies. GNSS attitude determination has developed rapidly [8,9,10]
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